With regards to migraine it is a common thing to smell things that are not there. If I smell 'Bush Fires' yep! it's a migraine that I can at least handle or though I might of had no other symtoms.

But if I smell 'Ether' (which I last went under at age 5) I am down for the count for days.

The 'Bush Fire' smell I have had upon waking and of course living in the country I race outside to double check. Once I realise it's nothing local, I know I need to get some OJ juice or try to go back to sleep ASAP. As for the other nothing really helps but a dark room doing nothing.

Vision pre cursor I get sometimes just a squizzel line, but when I get the middle crap I know it will be bad. Think of a retangle cut from righthand corner bottom to lefthand corner top, slightly move pieces apart and in the centre all I can see is nothing but a white misty mush.

At my worst with regards to vision. I actually lost all colour out of my vision other than brown and could only see out of one eye. Very scary!